The experiment was approved by the Institutional Animal Care and Use Committees of both Woods Hole Oceanographic Institution and the Bahamas Marine Mammal Research Organisation and the Animal Welfare and Ethics Committee of the University of St Andrews. “
“The aim of this study was to extend 40 yr of prior demographic work on northern elephant seals (Mirounga angustirostris) at Año Nuevo, California, by including the oldest animals. We used a Bayesian mark-recapture analysis to estimate lifelong survival and lifespan of a cohort of 372 weaned pups branded in 1985–1987 and resighted until 2008. Annual

survival probability of females averaged 86.3%/yr at ages 5–16, then declined until age 21, the age of the oldest female. Male survival was lower, averaging 67.7%/yr from buy GDC-0973 age 1 to age 15, the age of the oldest male. Northern elephant seal females in the expanding population at Año Nuevo live longer than southern elephant seal females (M. leonina) at colonies whose populations are declining. This comparison suggests that high survival of females is a key factor in population growth. The population of northern elephant

seals (Mirounga angustirostris) has been increasing in number and expanding in range since near extinction over CYC202 cell line a century ago (Townsend 1885, Bartholomew and Hubbs 1960, Stewart et al. 1994, Lowry 2002). The demographics of this growth phase have been documented at the Año Nuevo colony in central California over the last four decades, addressing variation in male survival and mating success, primiparity in females, pup mortality, and juvenile survivorship

(Le Boeuf 1974; Reiter et al. 1978, 1981; Le Boeuf and Reiter 1988; Reiter and Le Boeuf 1991; Clinton and Le Boeuf 1993; Le Boeuf et al. 1994). Most of this research focused on young animals and prime-age adults. The aim of this paper is to extend earlier work by documenting survival rates of the oldest animals, testing for mortality-related senescence, and comparing the lifespan of males and females. This yields a full life table for adult northern elephant seals of both sexes, necessary for understanding population growth of this long-lived mammal (Pistorius et selleck al. 1999, Eberhardt 2002). Our previous demographic studies were based on numbered plastic tags affixed to the interdigital webbing of the hind flippers. These worked well for studies of juveniles and young adults. With time, however, tags wore smooth or broke, necessitating retagging (Le Boeuf and Reiter 1988, Clinton and Le Boeuf 1993). Thus, survival estimates in older animals may be unreliable, even when tag loss is modeled (Pistorius et al. 2000, McMahon and White 2009). Branding offers a more permanent alternative for marking, and in southern elephant seals (Mirounga leonina) permitted identification of individuals throughout life without deleterious effects (Hindell 1991, McMahon et al.